Production of high octane gasoline



June 28, 1960 A. C. HANSEN, JR

PRODUCTION OF HIGH OC'IANE GASOLINE Filed June 13, 1957 Fractionation Reforming -40 P0/y Treating Cracking Crude Fractional/on INVE/V TOR: Andrew 6. flange/ Jr A T'TOR/VEYS United Stat P f tgo 2,943,038" PRODUCTIONOF HIGH ocraNE GASOLINE Filed June 13,1957, Sen-No.- 665,524

7' Claims. Ci. 208-49 The present invention relatesto a: novel-process 'for the production ofihigh octanegasoline and. comprises "a combination of mutually related and interdependent steps.

At the present time, high octane"- gasoline is obtained inone method by blending catalytically reformedt gasoline and. catalytically cracked gasoline, with. or without light-straight run fractions, and adding lead tetraethyl (TEL), to the blend. As the demand for higheroctane ,gasoline increases, it is necessary to increaseithe severity employed inthe catalytic reforming processand also to increase the concentration of TEI/added to. the gasoline blend. The increase in reforming. severity resultsindecreased yields and shortenedcatalystlife. The-increase the concentration of TEL. adds considerably" to the cost. oftthe gasoline. The present invention provides a novel combination process wherein the higher octane gasoline is obtained Without imposing excessive severity to thecatalytic reforming process and without increasing the. concentration of, TELtbeyond economical limits;

In. onecmbodiment the present invention relates to a 'combinationiprocessvfor producing high octane gasoline which comprises fractionating crude oil to separate a gasoline fraction from a higherboiling fraction, refo rming'said gasoline. vfractioninthe presence of. hydrogen to produce a highoctane gasoline fraction substantially 'free of olefinic' constituents, cracking saidihigher: boiling fraction toproduce a gasoline fractionscontainingoleconstitue'nts, separating the-llast-mentioned gasoline fraction and poly-treating the same to produce agasoline fraction of :re'diiced olefin. content and 'of. improved TEL susceptibility,-,and blending-at Ieasta portion of the last mentioned gasoline fraction? with. theIhighv octane gasoline fractiori' produced by said reforming.

" "TI-he invention to the accompanying flow diagrammatic drawing which illustrates several specific embodiments thereof.

Referring to the drawing, crudevoil is introduced to the process through line 1 and is supplied 'to crude fractionation zone}. In the interest .ofsimplicity,,zone 2 is illustrated'as a single column,-.,although it is understood that it may, comprise two or more separate fractionating zones,lwhich may be, operated at atmospheric, subatmosphen'c and/or superatmospheric. pressures. The 'e'xactco'n'ditions of operationof'the crude-fractionation will depend upon the particularlcrude oil charged and thepa'rt'icular, products desired; These. conditionsare well kn'own in'the art andjneed'notbe described in. detail in'the'present application, Regardless of the particular method employed,,the crude oil is separated into, a gasoline-fraction and a higher boilingfraction, along with whatever other fractions are desired. vIn oneemb'odiritent, the gasoline Lfraction comprises a full} boiling, range 'g'asolihafi icluding components having an'initialboiling fpoint'offfrom about 60. to. about 120 F. andan end boiling point of from about,350 to about 450 F'. The gasoline fraction is withdrawn from zone 2 throug'h line fund is *supplied throughdinef l tol reforming in the manner-w be'hreinatter same "In another embodiwill be explained furtherwith reference 2,943,038 l at'er teci- JimeZS; 1:060

'mentthe gasoline fraction comprisesa selected higher boiling-cut, generally referred to as naphtha and-having an initial boiling point within the range of fromabout 150 to about 300 F; and an endboiling point' within the range of from. about 350 F. to about 450 F. In this embodiment a light gasoline fraction'iswith'drawn from the upper portion of zone 2' through line 3 and is directed through a continuation'of this line for blending in'the manner .to be hereinafter set forth, while the high boiling'ga'soline fraction or so-'called naphtha' isWith' drawn from zone 2 through line 5 and is passed through line 4 for reforming in the manner to beh'ereinafter described:

In the embodiment-illustrated in the drawing, a: gas

oil fraction is separated :inzone 2 and withdrawn therefrom through lined and a higher boiling fraction is withdrawn from the lower portion of zone 2 through line 7. The composition of the fraction withdrawn through line 6 will vary with the particular refinery operation and may comprise com-- ponents'boilingas low as kerosene or heavy naphtha and. as high as reduced crude;

through line 7 from zone which process the charge and catalyst are maintained in a state of turbulence under hindered settling conditions'in a reaction zone. In this, process the catalyst iscontinuously supplied to a regeneration zone, wherein carbonaceous deposits are burned desired, all or a portion 7 v a recycledbywayof lines-15, Q ahdK FbQ CFEiQK iHg:

fromthe catalyst by contactwith anoxidizing gas; for example air, and the regenerated catalyst is continuously v returned to the reaction zone. cracking processes which may bed type, the moving. bed type'and the suspensoid type of operation. t Any suitable cracking catalysttmay be employed-gin Examples of other suitable zonelll and preferably comprisesa composite of silica o and alumina, thealumina comprising fromabout 5 to about 40% by weight of the catalyst composite and the remainder comprising silica.

alumina-zirconia, silica-thoria, silica-alumina-thoria, silica-mag'nesla, s1hca-alumina-magnesia and alumina-boria.

thetic catalyst may be prepared inany suitable manner. -The cracking through line 11 toffectiohation. zone 12. Here again,

zonelztmay comprise two orfm' ore' suitable separation zones. in the case illustrated, normally gaseousproduets are withdrawn from zone lz through line- 1 3, an y when products are withdrawn therefrom through line -14.-

for further conversion therein. Specialty product sene, diesel oil, fuel oil, or other selected producfm sent to cracking zone 10, while When it is desired to charge: a bottoms product from zone Ztocra'cking, this may be: accomplished by withdrawing the bottoms product, 2 and passing the same by 'way of lines 8, 9 and 6 to cracking zone 10. As hereinbefore set forth, it is understoodthat selected fractions desired: for other purposes may be Withdrawn, from zone 2' in any suitable manner, not :illustrated, and these fractions;

of kerosene; specialtynow known in the art "as be employed are the fixed I a Examples ofother suitable cracking catalysts are composites of silica-zirconia, silicaproducts areik directed from "zonevilfl of the heavy "prdducts iiiay "be 3 tions may be withdrawn from fractionating zone 12 in any suitable manner not illustrated.

Cracked gasoline is withdrawn from zone 12 through line 16 and is directed to poly-treating zone 17. In zone 17 the cracked gasoline is subjected at elevated temolefinie content of the gasoline.

In a preferred embodiment, the catalyst employed in zone 17 is a composite of phosphoric acid and kieselguhr, such a composite being available commercially under the name of solid phosphoric acid. This catalyst contains about 65-70% of higher H O content than the meta acid phosphoric acid and the remainder is kieselguhr. It is understood that any other suitable phosphoric acid catalyst may be employed in this step of the process. When using the solid phosphoric acid catalyst, the temperature employed is within the range of from about 350 to about 750 F. and preferably from about 400 to about 600 F. and the pressure is from about 100 to about 2000 pounds or more per square inch and preferably from about 500 to about 1500 pounds per square inch, utili..- ing a liquid hourly space velocity (defined as the volume of charge per hour per volume of catalyst in the reaction zone) of from about 0.1 to about and preferably from about 0.5 to about 5. With this catalyst, it is believed that the reactions which occur include those of oonjunct polymerization. This conjunct polymerization involves a plurality of reactions including the polymerization of olefins to higher olefins, cyclization of higher olefins to naphthenes, dehydrogenation of the naphthenes to aromatics, and hydrogenation of olefins present in the original gasoline to paraffins by the hydrogen formed in the aforesaid dehydrogenation. The net result of this operation is that a gasoline fraction of reduced olefin content is obtained since the polymerization, aromatization and hydrogenation all decrease olefin content.

In another embodiment, a catalyst of the same composition as that described above for use in the cracking step of the process is utilized in zone 17. This catalyst and particularly silica-alumina, silica-alumina-zirconia, silica-magnesia, or silica alumina-magnesia, serves to reduce the olefin content of the gasoline. In this embodiment, the temperature employed is below that used in the cracking operation and will range from about 500 to about 800 F. and preferablyfrom about 650 to about 750 F., and the pressure will range from atmospheric to 1500 pounds per square inch or more, and preferably from about 50 to about 500 pounds per square inch, while using a liquid hourly space velocity of from about 0.1 to about 10 and preferably from about 0.5 to

about 5. a

It is understood that reference to poly-treating and poly-treating catalyst includes the two. embodiments hereinbefore set forth. The range of operating conditions thus includes a temperature from about 350 to 800 F., a pressure from atmospheric to 2000 pounds per square inch or more, and a liquid hourly space velocity of from about 0.1 to about 10, the specific conditions being dependent upon the particular catalyst employed.

The poly-treated gasoline has a reduced olefin content. In some cases, the poly-treated gasoline will be 'of higher octane number than the cracked gasoline prior to' polytreating. In other cases, the octane number of the polytreated gasoline may be substantially the same as the untreated cracked gasoline but, in any event, the gasoline will be of improved susceptibility to tetraethyl lead and, therefore, will result in a higher octane number product upon the addition of the same concentration of tetraethyl lead than. is obtained with the untreated cracked naphtha. This, in turn, means that the reforming step of the process, to be hereinafter described,'may be operated at lower severity and, therefore, with longer catalyst life, and also that a lower concentrationof tetraethyl lead is required to obtain the high octane gasoline m es 1 perature to contact with a catalyst which reduces the 4 The poly-treated products are directed from zone 17 through line 18 into fractionation zone 19. Here again, it is understood that zone 19 may comprise two or more separation zones but, in the interest of simplicity, it is illustrated as a single zone. The separation effected in zone 19 will depend upon the particular refinery operation but, in general, will comprise separating normally gaseous components, gasoline boiling range components and higher boiling material. The gasoline components may be separated either as a single fraction or as a light gasoline and a heavy gasoline or naphtha fraction. The normally gaseous components are withdrawn from zone 19 through line 20 and may be supplied to any desired use. The heavier components are withdrawn from zone 19 through line 21 and may be withdrawn from the process or recycled, all or in part, by way of lines 22, 9 and 6 to cracking zone 10 for conversion therein into lower boiling material.

In the case illustrated in the drawing, a light gasoline fraction is withdrawn from zone 19 through line 23 and a heavy gasoline fraction is withdrawn therefrom through line 24. The specific split between the light and heavy gasolines may vary with the particular refinery operation. Generally the end boiling point of the light fraction and accordingly the initial boiling point of the heavy fraction will be within the range of from about 150 to about 250 F. At least a portion of the poly-treated gasoline is blended with the reformed products in the manner to be hereinafter set forth.

The full boiling range gasoline or the naphtha fraction withdrawn from crude fractionation zone 2 by way of line 4 is subjected to reforming in zone 25. The reforming is etfected in the presence of hydrogen introduced to the process through line 26 and supplied to zone 25 through lines 27 and 4 and/or hydrogen recycled within the process in the manner to be hereinafter described.

The reforming is effected at a temperature of from about 800 to about 1100 F. and preferably from about 900 to about 1000 F. and a pressure of from about to about 2000 pounds per square inch and preferably from about 500 to about 1000 pounds per square inch,

utilizing a space velocity of from about 0.1 to about 10 and preferably from about 1 to about 5. a Any suitable reforming catalyst may be employed and preferably a platinum-containing catalyst is used. A particularly desirable reforming process is the platforming process which utilizes a catalyst comprising a composite of alumina, platinum in a concentration of from about 0.1 to about 3% by weight and combined halogen in a concentration of from about 0.2 to'about 8% by weight Other platinum containing catalysts comprise composites of platinum with silica-alumina, silica-zirconia, silica magnesia, or the like, preferably treated to reduce cracking activity, or platinum composited with alumina, silica or other suitable carriers. In some cases, catalysts comprising composites of alumina-molybdenum oxide, alumina-molybdenum oxide-cobalt oxide, alumina-vanadium oxide, or the like, which composites also may contain silica, may be used in the reforming step of the present process, but generally these catalysts are not as effective as the platinum-containing catalysts for producing high octane gasoline.

Regardless of the particular reforming process employed, more severe operation is required to obtain higher octane products. As the severity, including increased temperature and pressure and decreased space velocity, is increased, the activity of the catalyst is adversely, affected. One explanation is that the use of more severe conditions results in the simultaneous production of by-products which deactivate'thecatalyst. The platforming? process is flexible and can withstand high severity, but even in this process there is a point where the increased severity does impair the catalyst life. Therefore,- it is advantageous to operate the reforming process at the lowest severity which produce a gasoline of satisfactory "arises octane number upon blending with other gasoline fractlons. For example, it generally is necessary to produce a reformed gasoline of higher octane number than the final blended product because the reformed'ga'soline. is a hydrogen is withdrawn from the upper portion of zone 29 through line 30 and, while a portion vmaybe with? drawn through an extension of line' 26, at-least a portion of the hydrogen preferably'is recycled by way of lines 26, 27 and 4 to reforming zone 25. Thepa rticular separation of the reformed gasoline in zone 29 will depend upon the refinery market conditions andthese include both aviation gasoline andmotor gasoline. In one embodiment, aviation gasoline or high octane motor gasoline is formed by separating the reformate into a light fraction and a heavy fraction in zone 29, the light fraction being withdrawn through line 30 and blended with all or a portion of the light straight run fraction separated in zone 2 and passed by way of lines 3 and 31 to commingle with the light reformate in line 30. When desired, poly-treated gasoline, and particularly the light fraction thereof, may be directed by way of lines 23 and 32 to blend with the gasoline in line 30. Also, when desired, all or a portion of the heavy reformate separated in fractionation zone 29 may be withdrawn through lines 33 or lines 34 and 35 and directed through lines 36 and 37 to blend with the gasoline in line 30. In another embodiment, two separate blends of gasolines are produced, one blend comprising the light gasoline fraction separated in zone 2 with the low boiling reformate as hereinbefore described, and the other comprising a blend of heavy reformate and the poly-treated gasoline. In this embodiment, the poly-treated gasoline, either full boiling range or a light fraction thereof, is withdrawn from zone 19 through line 23 and directed through lines 32 and 38 to line 36, where it blends with heavy reformate withdrawn from zone 29 through lines 33 or 35. In some cases, depending upon the particular refinery operation, a portion of the light gasoline fraction separated in zone 2 is directed through lines 3 and 39 to commingle with the blend in line 36. It will be seen from the above description that the present processprovides great flexibility in permitting the refiner'to prepare different blends to meet the market demands.

further the noyelty and utility of the. present inventionbu t not with the intentioniof'unduly limitinglthe same.

e 7 Example I" A Kuwaitcrudeoil is subjected to atmospheric and vacuum distillation. in. aseries of zones to separa'teabout by volume of a light gasoline fraction havingvan end boiling point of: 200 F., about 13% by volume of a naphtha fraction having aboiling range of from about As hereinbefore set forth, fractionation in zone 29 will depend upon the particular operation desired and, in some cases, means may be provided for the withdrawal of a heavy reformate bottoms through line 34 for other uses. Similarly, in some cases, the poly-treated gasoline is separated in zone 19 into a light and heavy fraction and only the light fraction is used for blending. The heavy fraction then is supplied by way of lines 24 and 40 into line 4 to be subjected to reforming in zone 25 for the production of high octane gasoline components to be used in the blend or otherwise as desired.

From the above description, it is seen that an improved process for the production of high octane gasoline is presented. The poly-treating step of the process permits .lower severity operation in the reforming zone and this results in longer on-stream times with the concomitant increased efficiency thereof. The cracking step of the process furnishes the cracked gasoline as charge to the poly-treating step of the process.

In theinterest of simplicity, valves, pumps, heaters 200 to about 400 vF., andabout 15% by weight o'f gas oil, inaddition to. other fractions desired for-other use-s, includingkerosenes, diesel fuel andiasphalth The gas" oil fraction is subjected to catalytic cracking in 'a fluidized operation, utilizing a silica-alumina catalyst,

at a temperature of'about 900? F. and asuper'atmofs pheric, pressure .of about 1 0 pounds per squareirj'ch.

This results in the production of about 50% byvolume of cracked gasoline. This cracked gasolineis'subj'ected to poly-treating in thepresence of a solid phosphoric acid catalyst at a temperature of 500 F.i and'a pressure of 1000 pounds per square inch, utilizing a liquid hourly space velocity of about 3'. T he poly-treated gas oline is fractionated toseparate a light fraction having an end boiling .point of about 200 F. and a heavy gasoline fraction having an end boiling point of about 400 F. The bromine number of the cracked gasoline is reduced from about 50 to less than about 20.

The naphtha originally separated from the crude oil is subjected to reforming in the presence of hydrogen in a mol ratio to hydrocarbon of 10:1, at a temperature of 1000" F. and a pressure of 500 pounds per square inch in the presence of a catalyst comprising alumina, about 0.4% by weight of platinum and about 0.4% by weight of combined halogen, the latter comprising a mixture of combined fluorine and combined chlorine. The reformed products are fractionated to separate a gasoline fraction having a clear octane number of about 95. Hydrogen separated from the reformed products is recycled within the process.

The reformed gasoline of clear octane number is.

blended with the light poly-treated fraction and with the light straight run gasoline previously separated in the first fractionation. Tetraethyl lead is added in a concentration to produce a final blend of leaded octane number. In addition to being of this high octane number, the blend is a full boiling range gasoline and is readily marketable as premium motor fuel.

When it is desired to also produce aviation gasoline, the different streams are blended to produce the aviation gasoline, to which tetraethyl lead is added to obtain the required octane number, and the remaining products are blended to produce only premium motor fuel or a mixture of premium and regular motor fuel "as desired. From the above, it is apparent that considerable benefits are obtained by the novel combination process herein set forth.

Example II than 20, and the leaded octane number of the gasoline.

is increased about 7 numbers over that obtained with the untreated cracked gasoline.

I claim as my invention:

, arate a gasoline fraction and a higher boiling fraction,

reforming said gasoline fraction in'the presence of hydrogen to produce a high octane gasoline fraction sub stantially free of olefinic constituents, cracking said '1. A combination process for producing high octane gasoline which comprises fractionating crude oil to sep higher boiling fraction to produce a gasoline fraction containing olefinic constituents, separating the last mentioned gasoline fraction and poly-treating the same to produce a gasoline fraction of reduced olefin content and of improved TEL susceptibility, and blending at least a portion of the last mentioned gasoline fraction with the high octane gasoline fraction produced by said reforming.

2. The process of claim 1 further characterized in that said reforming is efiected in the presence of a catalyst comprising alumina and platinum.

3. The process of .claim 2 further characterized in that said catalyst also contains combined halogen,

4. The process of claim 1 further characterized in that said poly-treating is effected in the presence of a solid catalyst containing phosphoric acid, at a temperature of from about 350. to about 750 'F. and a pressure of from about 100 to about 2000 pounds per square inch.

. 5.'The process of claim 1 further characterized in that said poly-treating is effected in the presence of a catalyst comprising silica and alumina, at a tempera ture of from about 500 to about 800 F. and a pres- 8 sure of from about atmospheric to about 1500 pounds per square inch.

6. The process of claim 1 further characterized in that said first-mentioned gasoline fraction comprises a heavy gasoline fraction which is subjected to reforming, a light gasoline fraction also is separated by fractionation of said crude oil, and a portion of the light gasoline fraction is blended with the reformed gasoline and polytreated gasoline fractions.

7. The process of claim 1 further characterized in that the gasoline fraction from said poly-treating is seperated into light and heavy fractions, the light fraction being blended with at least a portion of the reformed gasoline fraction, and the heavy fraction is subjected to reforming in commingled state with said first-mentioned gasoline fraction.

References Cited in the file of this patent UNITED STATES PATENTS 2,354,866 Lang Aug. 1, 1944 2,384,339 Read Sept. 4, 1945 2,415,530 Porter Feb. 11, 1947 -2,479,110 Haensel Aug. 16, 1949 

1. A COMBINATION PROCESS FOR PRODUCING HIGH OCTANE GASOLINE WHICH COMPRISES FRACTIONATING CRUDE OIL TO SEPARATE A GASOLINE FRACTION AND A HIGHER BOILING FRACTION, REFORMING SAID GASOLINE FRACTION IN THE PRESENCE OF HYDROGEN TO PRODUCE A HIGH OCTANE GASOLINE FRACTION SUBSTANTIALLY FREE OF OLEFINIC CONSTITUENTS, CRACKING SAID HIGHER BOILING FRACTION TO PRODUCE A GASOLINE FRACTION CONTAINING OLEFINIC CONSTITUENTS, SEPARATING THE LAST MEN- 